mid-13c., daunger, "arrogance, insolence;" c. 1300, "power of a lord or master, jurisdiction," from Anglo-French daunger, Old French dangier "power, power to harm, mastery, authority, control" (12c., Modern French danger), alteration (due to association with damnum) of dongier, from Vulgar Latin *dominarium "power of a lord," from Latin dominus "lord, master," from domus "house" (from PIE root *dem- "house, household").

Modern sense of "risk, peril, exposure to injury, loss, pain, etc." (from being in the control of someone or something else) evolved first in French and was in English by late 14c. For this, Old English had pleoh; in early Middle English this sense is found in peril. For sound changes, compare dungeon, which is from the same source.

late 15c., from en- (1) "make, put in" + danger. Related: Endangered; endangering. Endangered species recorded by 1958.

c. 1200, daungerous, "difficult to deal with, arrogant, severe" (the opposite of affable), from Anglo-French dangerous, Old French dangeros (12c., Modern French dangereux), from danger "power, power to harm, mastery, authority, control" (see danger).

In Chaucer, it can mean "hard to please; reluctant to give; overbearing." The modern sense of "involving danger, hazardous, unsafe, risky, liable to inflict injury or harm" is from c. 1400. Other words formerly used in this sense included dangersome (1560s), dangerful (1540s). Related: Dangerously.

Proto-Indo-European root meaning "house, household." It represents the usual Indo-European word for "house" (Italian, Spanish casa are from Latin casa "cottage, hut;" Germanic *hus is of obscure origin).

It forms all or part of: Anno Domini; belladonna; condominium; dame; damsel; dan "title of address to members of religious orders;" danger; dangerous; demesne; despot; Dom Perignon; domain; dome; domestic; domesticate; domicile; dominate; domination; dominion; domino; don (n.) "Spanish, Italian, and Portuguese title of respect;" Donna; dungeon; ma'am; madam; madame; mademoiselle; madonna; major-domo; predominant; predominate; timber; toft.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit damah "house;" Avestan demana- "house;" Greek domos "house," despotēs "master, lord;" Latin domus "house," dominus "master of a household;" Armenian tanu-ter "house-lord;" Old Church Slavonic domu, Russian dom "house;" Lithuanian dimstis "enclosed court, property;" Old Norse topt "homestead."

"danger, risk, hazard, jeopardy, exposure of person or property to injury, loss, or destruction," c. 1200, from Old French peril "danger, risk" (10c.), from Latin periculum "an attempt, trial, experiment; risk, danger," with instrumentive suffix -culum and first element from PIE *peri-tlo-, suffixed form of root *per- (3) "to try, risk."

"to guard, protect, keep secure from danger," mid-15c., from safeguard (n.). Related: Safeguarded; safeguarding.

1590s, "involving risk or danger," from un- (1) "not" + safe (adj.).

"one who shirks duty or danger," 1799, agent noun from shirk (v.).

"action taken in response to a danger or threat," 1855, from counter- + measure (n.).

"threatening, indicating danger or risk," early 15c., present-participle adjective from menace (v.). Related: Menacingly.